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1. Initiator-dependent kinetics of lyotropic liquid crystal-templated thermal polymerization

   https://doi.org/10.1039/D1PY00127B  

   Saadat, Younes; Kim, Kyungtae; Foudazi, Reza (April 2021, Polymer Chemistry)

   null (Ed.)

   In this study, we examine the polymerization kinetics with different thermal initiators in lamellar and hexagonal lyotropic liquid crystal (LLC) structures directed by Pluronic L64. Ammonium persulfate is used to initiate the polymerization from the water phase, whereas azobisisobutyronitrile and benzoyl peroxide are employed to commence the reaction through the monomer phase. While the mesophase structure remains intact for all the initiation systems, the kinetics of polymerization and conversion vary significantly. The obtained differential scanning calorimetry (DSC) results reveal that, under the same conditions, the initiation from water (IFW) system results in enhanced reaction rates as well as higher monomer conversions compared to the initiation from oil (IFO) system. A higher termination rate in LLC nanoconfinements induces lower reaction rates in the IFO system. Moreover, our work on different LLC structures shows that the effect of nanoconfinement on the polymerization rate can be minimized through IFW. Chemorheology not only confirms the results obtained from DSC, but also shows that, in similar monomer conversions, the polymers obtained from the IFW system exhibit improved mechanical properties over the samples produced through the IFO process. 

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2. Dynamic Assembly of Strong and Conductive Carbon Nanotube/Nanocellulose Composite Filaments and Their Application in Resistive Liquid Sensing

   https://doi.org/10.1021/acsami.3c03906  

   Wise, Heather G.; Takana, Hidemasa; Dichiara, Anthony B. (August 2023, ACS Applied Materials & Interfaces)

   The continuous flow assembly of colloidal nanoparticles from aqueous suspensions into macroscopic materials in a field-assisted double flow focusing system offers an attractive way to bridge the outstanding nanoscale characteristics of renewable cellulose nanofibrils (CNFs) at scales most common to human technologies. By incorporating single-walled carbon nanotubes (SWNTs) during the fabrication process, high-performance functional filament nanocomposites were produced. CNFs and SWNTs were first dispersed in water without any external surfactants or binding agents, and the resulting nanocolloids were aligned by means of an alternating electric field combined with extensional sheath flows. The nanoscale orientational anisotropy was then locked by a liquid−gel transition during the materials assembly into macroscopic filaments, which greatly improved their mechanical, electrical, and liquid sensing properties. Significantly, these findings pave the way toward the environmentally friendly and scalable manufacturing of a variety of multifunctional fibers for diverse applications. 

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3. Lyotropic liquid crystals as templates for advanced materials

   https://doi.org/10.1039/D1TA02748D  

   Saadat, Younes; Imran, Omar Q.; Osuji, Chinedum O.; Foudazi, Reza (October 2021, Journal of Materials Chemistry A)

   Lyotropic liquid crystals (LLCs) have drawn attention in numerous technical fields as they feature a variety of nanometer-scale structures, processability, and diverse chemical functionality. However, they suffer from poor mechanical properties and thermal stability. Polymerization in LLCs, referred to as LLC templating, is an effective approach to overcome this issue. While the templating approach results in robust mechanical, physical, and thermal properties, retention of the parent LLC structure after polymerization has been a major concern in the field. Therefore, there have been several efforts to introduce new materials and techniques to preserve the native LLC nanostructure after polymerization. In this review, we survey the efforts put in this area along with the applications of the obtained materials from LLC templating, after providing a brief introduction of LLC structures. Moreover, polymerization kinetics in different LLC structures, as a key player in the structure retention, are analyzed. Furthermore, we discuss the outlook of the field and available opportunities. 

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4. Fluorescent surfactants from common dyes – Rhodamine B and Eosin Y

   https://doi.org/10.1515/pac-2019-0219  

   Smith McWilliams, Ashleigh D.; Ergülen, Selin; Ogle, Meredith M.; de los Reyes, Carlos A.; Pasquali, Matteo; Martí, Angel A. (July 2019, Pure and Applied Chemistry)

   Abstract Eight fluorescent surfactants were synthesized by attaching aliphatic chains of 6, 10, 12, or 16 carbons to the fluorescent dyes Rhodamine B and Eosin Y. The obtained critical micelle concentrations (CMC) demonstrate an increasing CMC with decreasing aliphatic chain length, which is a typical behavior for surfactants. Additionally, fluorescence quantum yield experiments show a decrease in quantum yield with increasing aliphatic chain length, suggesting that the tails can interact with the dye, influencing its excited state. Finally, applications for the fluorescent surfactants were demonstrated; as a cellular stain in Panc-1 cells and as a dispersion and imaging tool for carbon and boron nitride nanotubes. These surfactants could provide a useful tool for a wide array of potential applications, from textile dyes to fluorescence imaging. 

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5. Multiple Relaxations and Entanglement Behaviors of Polymerized Ionic Liquids with Various Anions/Cations

   https://doi.org/10.1021/acs.macromol.4c01844  

   Liu, Gang; Larson, Ronald G; He, Xi; Dan, Yongjie; Niu, Yanhua; Li, Guangxian (January 2025, Macromolecules)

   Hillmyer, MA (Ed.)

   Polymerized ionic liquids (PILs) with anions of bis(trifluoromethylsulfonyl)imide (TFSI−), hexafluorophosphate (PF6−), and tetrafluoroborate (BF4−); and cations of poly[1-(4-vinylbenzyl)-3-alkyl-imidazolium] P[VBCnIM]+ with alkyl lengths C1, C2, C4 were successfully synthesized and characterized. X-ray scattering showed an increase of backbone-to-backbone spacing (db) by 0.8 Å per CH2 added to the alkyl side chain. Rheological and dielectric measurements were used to measure rates of chain relaxation and ion dissociation/association. The glass transition temperatures Tg follow the trend: PC4-TFSI < PC2-TFSI < PC1-TFSI< PC1-BF4 < PC1-PF6, which correlates well with their dielectric behaviors. However, the fragility mDR from dielectric relaxation increases with decreasing Tg, which is the opposite of the dependence of the fragility mRheo from rheology for both our PILs and of neutral polymers. The dielectric and rheological relaxations of our PIL’s are expected to be influenced by both their anion-cation binding energies and their relative free volumes, while for neutral polymers, only free volume influences relaxation. The increase of fragility of mDR with decreasing Tg, therefore suggests that dielectric relaxation is influenced more by anion-cation binding energy than by free volume, while the reverse is true for mRheo. The plateau modulus GN and entanglement molecular weight Me estimated from rheological measurements agree with predictions of the packing model, using only a small modification of the Flory characteristic ratio C∞ from that of a neutral polymer. Packing lengths of p= 6.0 ~ 9.3 Å and tube diameters dt= 11 ~ 17 nm are found, depending on specific cation and anion structures. 

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